With globalization of microbial threats and an increasing appreciation for the role of infection in chronic as well as acute diseases, there is burgeoning interest in the development of specific antiviral drugs. Less attention has been focused on the establishment and implementation of rapid viral diagnostic methods, without which it will not be possible to obtain the full benefit of new therapies. Here we review the current status of viral diagnostics and the utility of various sequence-based diagnostic platforms for applications in clinical microbiology, surveillance and pathogen discovery.